At the time this was created and/or cut and pasted, it may or may not have been as ambiguous as other allegedly less confusing definitions.
This is not cut or pasted, I created it as an amalgamation of several other definitions and facts. I think it could be better worded though ( I didn't polish the definition); The problem polishing the definition is that you have to go back to some time in the past, and it is not at all clear exactly what that time might be. Recorded deeds for property may go back hundreds of years, and buildings built and torn down several times, multiple land use changes. So what is time zero? For construction, it is a bit easier, you can probably refer to "original construction". It gets cloudy with the likes of historical properties. Land is a *****, Typically goes something like agricultural use to subdivision. What about commercial, that's even more difficult in some cases.
Have to think about the polishing aspect.
From a problem-solving perspective, I'm influenced mostly by what is right around me. The City of Pacifica does variances, with town meetings on community TV, neighbors have their say, both residential and commercial and there is a vote, not to forget hired attorneys, engineers, contractors, and other professionals. Everything is a bit fluid and in flux. Complex, with many zones, the Coastal Commission, the environmentalists. Earthquake, landslide, flooding, forest fire country. Mixed-use and commercial in the middle of residential. Ocean view, mountain view, partially obstructed or not, and so on and so forth. Don't forget the endangered frogs, butterflies and you name it. Oh yea, "non-conforming" - a slippery slope.